Induction cooktops are devices which exploit the phenomenon of induction heating for food cooking purposes. Induction cooktops comprise a top made of glass-ceramic material upon which cooking units are positioned (hereinafter “pans”). Moreover there are provided inductors comprising coils of copper wire where an oscillating current (e.g. an alternating current) is circulated producing an oscillating electromagnetic field.
The electromagnetic field has the main effect of inducing a parasitic current inside the pan, which is made of an electrically conductive ferromagnetic material. The parasitic current circulating in the pan produces heat by dissipation; such heat is generated only within the pan and it acts without heating the cooktop.
This type of flameless cooktop has a better efficiency than electric cooktops (i.e. a greater fraction of the absorbed electric power is converted into heat that heats the pan). In addition, induction cooktops are safer to use due to the absence of hot surfaces or flames, reducing the risk of burns for the user or of fire. The presence of the pan on the cooktop causes the magnetic flux close to the pan itself causing the power to be transferred towards the pan. The greater the size of the pan, the higher the power that can be transferred.
Since heat is generated by induced currents, a cooktop control system may be utilized to monitor currents flowing through the coils; in this way, the power supplied to each inductor can be adjusted. Moreover such current monitoring may provide for the control system to automatically detect a presence of a pan over the inductors and to automatically turn off the inductors in response to the absence of the pan on the cooktop. A drawback arising from the automatic detection, is that it is possible for small pans not to be detected by the control system. In such conditions, the presence of a small pan that is not detected by the control system may lead to the cooktop control system failing to activate the inductors. That is, the control system may fail to activate the passage of the current through the coils of the inductors and fail to heat the small pan.
The disclosure provides for a control system configured to provide an improved method of presence detection for pans, particularly small pans. The modification provides for improved detection and operation of an induction cooktop.